Pondless stream depth
I am in need of some advice about the maximum depth for pondless streams. We are planning to put a waterfall and stream into our duck aviary(mandarins) and would like a section of it to be fairly deep. Ideally 12-18 inches deep with a shallow beach area opposite it to allow the babies to get in and out easily. Then another section of it be about 9 inches deep. The stream we are planning is approx. 25 feet long but at its widest it's only 3.5 feet wide the rest of it averages 1 foot. I searched all over but couldn't really find an answer on the do's and donts for the depths of pondless waterfalls. While I'm here asking questions (and no doubt sounding very silly) what size reservoir would I need. The area we have for the reservoir is not large but the ground is good and we can dig down further very easily. Thank you all for any advice!!!!
i have included a rough layout of the stream we have in mind. Each square is one foot. The the area of the stream with the hash marks is where it would be the deepest. Hopefully it's clear as mud.